textproduct: Quad Cities

KEY MESSAGES

- There is the chance for a portion of the MCS activity occurring across South Dakota to move southeastward enough to impact portions of the local area from late morning into early afternoon, possibly as strong to severe storms.

- A prolonged period of very hot and humid conditions will be seen starting today (in the south) and lasting through much of the upcoming work week, with peak heat index values upwards to 105 degrees or higher. Extreme Heat Warnings continue for this upcoming hot spell.

- Precipitation chances will remain limited through midweek, increasing each day from Thursday onward. The chance for showers/storms and resultant cloud cover may have an impact on forecast high temperatures as we approach the July 4th weekend.

SHORT TERM /THROUGH WEDNESDAY NIGHT/

Issued at 235 AM CDT Sun Jun 28 2026

Ongoing MCS acrs southeast SD and far northeast NE looks like it may be going to be a fcst buster for today for at least portions of the local area. Several MCS maintenance parameters and instability/THTA-E gradients bend southeastward and tighten from northwest IA into southeastern to east central IA as the morning progresses. A warm front trying to retreat as well acrs IA all spell trouble with regards to a portion of the MCS propagating east-southeastwrad enough to impact the DVN CWA from late morning into mid afternoon, especially along and north of the I-80 corridor. The extent of shear and building thermodynamic energy support damaging winds to 70 MPH and large hail even if partially elevated. If a sfc root becomes established, LLVL shear/southeast BL flow supports some meso-vortice spin up tornadoes. But all this will be encountering an upper level ridge trying to amplify right acrs the MS RVR Valley as well as building EML between H8-H7 MB which could act as a storm "eater". Several of the latest CAM runs continue to be bullish in maintaining the MCS into our area either along and north of I-80, Hwy 30, or Hwy 20. This while some CAMs and favored deterministic 00z run ECMWF and GFS erode this convection as it arrives or deflects it north of the area in an elevated state.

Have to think/bet on that some of this is going to make it and walked a swath of 20-30 POPs acrs the north half of the DVN CWA from after 15z to 21z or so. Will also go with a NW-to-SE oriented narrow POP swath to account for a connecting elevated warm air advection wing of a linear stripe of broken to isolated showers and possible thunder connecting to the incoming lift of associated MCV.

If this MCS can make it acrs if even in a decaying form, cloud cover/debris/cool outflow looks like it will move acrs at least the Extreme Heat Watch areas. And new Heat Index values for today are marginal in the mid to upper 90s in those areas. Thus have cancelled the EH watch for today and tonight in those areas, and replaced it with an upgrade to an Extreme Heat Warning starting at 17z Monday. More confidence in dry hot conditions with high DPTs to make warning criteria on Monday so as why to make this move now. The rest of the Warning continues as is for now for multi-day Heat Index's of 100- 110, with later shifts assessing the need to extend into the mid or even late week. This depends on cloud debris and edging closer to the western edge of the thermal ridge and ring of fire as early as late Tue and growing in potential Wed through Thu/Fri.

LONG TERM /THURSDAY THROUGH SATURDAY/

Issued at 235 AM CDT Sun Jun 28 2026

Thursday onward through the holiday weekend, we will start to see the strong ridge over the Central CONUS break down a little and start to shift east. This easterly shift will result in upper waves tracking closer/over our area, leading to increasing precipitation chances. Thus, there are uncertainties in the temperature forecast as we approach the July 4th weekend. Overall, we are expected to remain hot and humid. If we avoid the storm track, it is possible that the oppressive heat will continue, but if we fall under the storm track, temperatures may be lower than currently forecast. Currently, precipitation chances are not very high, but we do have 20-40% PoPs each day Thursday onward. Forecast would favor the potential for diurnally driven storms with such hot and humid conditions, with the chance for overnight ring of fire convection that may result in convective debris into the daytime. This convective debris would be a limiting factor on the high temperature forecast.

AVIATION /12Z TAFS THROUGH 12Z MONDAY/

Issued at 545 AM CDT Sun Jun 28 2026

Plenty of variable CIGs acrs the area this morning, but most areas MVFR. Will trend the CIGs to diurnally lift to VFR and decrease a bit in coverage from south to north as the day progresses and a warm front tries to retreat northward through the region. The other fcst challenge will be for the potential for a portion of the northwest IA MCS to maintain and propagate east-southeastwrad and make it into portions of the area(especially north of I-80) from late morning into early afternoon. These storms may be strong to severe with gusty winds and hail if they can maintain their strength. They may effect the TAF sites CID, DBQ, and possibly the MLI. For now will continue to use PROB30 groups for trying to time out a 2-hour window of impact at those sites until there is more confidence that they will make it this far south and hold together. After that, VFR into Sunday night. Away from the storms, ambient sfc winds will be gusty southeasterly up to 25 KTs.

DVN WATCHES/WARNINGS/ADVISORIES

IA...Extreme Heat Warning from noon Monday to 9 PM CDT Tuesday for IAZ040>042-053-054-066. Extreme Heat Warning from 1 PM this afternoon to 9 PM CDT Tuesday for IAZ051-052-063>065-067-068-076>078-087>089- 098-099. IL...Extreme Heat Warning from noon Monday to 9 PM CDT Tuesday for ILZ001-002-007-009-016>018. Extreme Heat Warning from 1 PM this afternoon to 9 PM CDT Tuesday for ILZ015-024>026-034-035. MO...Extreme Heat Warning from 1 PM this afternoon to 9 PM CDT Tuesday for MOZ009-010.